update tests status badge in readme

Author: vsergeev

README.md

@@ -1,4 +1,4 @@
-# u-msgpack-python [![Build Status](https://app.travis-ci.com/vsergeev/u-msgpack-python.svg?branch=master)](https://app.travis-ci.com/github/vsergeev/u-msgpack-python) [![Docs Status](https://readthedocs.org/projects/u-msgpack-python/badge/)](https://u-msgpack-python.readthedocs.io/en/latest/) [![GitHub release](https://img.shields.io/github/release/vsergeev/u-msgpack-python.svg?maxAge=7200)](https://github.com/vsergeev/u-msgpack-python) [![License](https://img.shields.io/badge/license-MIT-blue.svg)](https://github.com/vsergeev/u-msgpack-python/blob/master/LICENSE)
+# u-msgpack-python [![Tests Status](https://github.com/vsergeev/u-msgpack-python/actions/workflows/tests.yml/badge.svg)](https://github.com/vsergeev/u-msgpack-python/actions/workflows/tests.yml) [![Docs Status](https://readthedocs.org/projects/u-msgpack-python/badge/)](https://u-msgpack-python.readthedocs.io/en/latest/) [![GitHub release](https://img.shields.io/github/release/vsergeev/u-msgpack-python.svg?maxAge=7200)](https://github.com/vsergeev/u-msgpack-python) [![License](https://img.shields.io/badge/license-MIT-blue.svg)](https://github.com/vsergeev/u-msgpack-python/blob/master/LICENSE)
 
 u-msgpack-python is a lightweight [MessagePack](http://msgpack.org/) serializer and deserializer module written in pure Python, compatible with Python 2 and 3, as well CPython and PyPy implementations of Python. u-msgpack-python is fully compliant with the latest [MessagePack specification](https://github.com/msgpack/msgpack/blob/master/spec.md). In particular, it supports the new binary, UTF-8 string, application-defined ext, and timestamp types.